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-rw-r--r--gcc/range-op-float.cc81
-rw-r--r--gcc/testsuite/gcc.c-torture/execute/ieee/pr109008.c18
2 files changed, 75 insertions, 24 deletions
diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc
index ff42b95..63b7ad1 100644
--- a/gcc/range-op-float.cc
+++ b/gcc/range-op-float.cc
@@ -2199,6 +2199,33 @@ zero_to_inf_range (REAL_VALUE_TYPE &lb, REAL_VALUE_TYPE &ub, int signbit_known)
}
}
+/* Extend the LHS range by 1ulp in each direction. For op1_range
+ or op2_range of binary operations just computing the inverse
+ operation on ranges isn't sufficient. Consider e.g.
+ [1., 1.] = op1 + [1., 1.]. op1's range is not [0., 0.], but
+ [-0x1.0p-54, 0x1.0p-53] (when not -frounding-math), any value for
+ which adding 1. to it results in 1. after rounding to nearest.
+ So, for op1_range/op2_range extend the lhs range by 1ulp in each
+ direction. See PR109008 for more details. */
+
+static frange
+float_widen_lhs_range (tree type, const frange &lhs)
+{
+ frange ret = lhs;
+ if (lhs.known_isnan ())
+ return ret;
+ REAL_VALUE_TYPE lb = lhs.lower_bound ();
+ REAL_VALUE_TYPE ub = lhs.upper_bound ();
+ if (real_isfinite (&lb))
+ frange_nextafter (TYPE_MODE (type), lb, dconstninf);
+ if (real_isfinite (&ub))
+ frange_nextafter (TYPE_MODE (type), ub, dconstinf);
+ ret.set (type, lb, ub);
+ ret.clear_nan ();
+ ret.union_ (lhs);
+ return ret;
+}
+
class foperator_plus : public range_operator_float
{
using range_operator_float::op1_range;
@@ -2214,8 +2241,9 @@ public:
range_op_handler minus (MINUS_EXPR, type);
if (!minus)
return false;
- return float_binary_op_range_finish (minus.fold_range (r, type, lhs, op2),
- r, type, lhs);
+ frange wlhs = float_widen_lhs_range (type, lhs);
+ return float_binary_op_range_finish (minus.fold_range (r, type, wlhs, op2),
+ r, type, wlhs);
}
virtual bool op2_range (frange &r, tree type,
const frange &lhs,
@@ -2260,9 +2288,10 @@ public:
{
if (lhs.undefined_p ())
return false;
- return float_binary_op_range_finish (fop_plus.fold_range (r, type, lhs,
+ frange wlhs = float_widen_lhs_range (type, lhs);
+ return float_binary_op_range_finish (fop_plus.fold_range (r, type, wlhs,
op2),
- r, type, lhs);
+ r, type, wlhs);
}
virtual bool op2_range (frange &r, tree type,
const frange &lhs,
@@ -2271,8 +2300,9 @@ public:
{
if (lhs.undefined_p ())
return false;
- return float_binary_op_range_finish (fold_range (r, type, op1, lhs),
- r, type, lhs);
+ frange wlhs = float_widen_lhs_range (type, lhs);
+ return float_binary_op_range_finish (fold_range (r, type, op1, wlhs),
+ r, type, wlhs);
}
private:
void rv_fold (REAL_VALUE_TYPE &lb, REAL_VALUE_TYPE &ub, bool &maybe_nan,
@@ -2338,13 +2368,14 @@ public:
range_op_handler rdiv (RDIV_EXPR, type);
if (!rdiv)
return false;
- bool ret = rdiv.fold_range (r, type, lhs, op2);
+ frange wlhs = float_widen_lhs_range (type, lhs);
+ bool ret = rdiv.fold_range (r, type, wlhs, op2);
if (ret == false)
return false;
- if (lhs.known_isnan () || op2.known_isnan () || op2.undefined_p ())
- return float_binary_op_range_finish (ret, r, type, lhs);
- const REAL_VALUE_TYPE &lhs_lb = lhs.lower_bound ();
- const REAL_VALUE_TYPE &lhs_ub = lhs.upper_bound ();
+ if (wlhs.known_isnan () || op2.known_isnan () || op2.undefined_p ())
+ return float_binary_op_range_finish (ret, r, type, wlhs);
+ const REAL_VALUE_TYPE &lhs_lb = wlhs.lower_bound ();
+ const REAL_VALUE_TYPE &lhs_ub = wlhs.upper_bound ();
const REAL_VALUE_TYPE &op2_lb = op2.lower_bound ();
const REAL_VALUE_TYPE &op2_ub = op2.upper_bound ();
if ((contains_zero_p (lhs_lb, lhs_ub) && contains_zero_p (op2_lb, op2_ub))
@@ -2363,7 +2394,7 @@ public:
// or if lhs must be zero and op2 doesn't include zero, it would be
// UNDEFINED, while rdiv.fold_range computes a zero or singleton INF
// range. Those are supersets of UNDEFINED, so let's keep that way.
- return float_binary_op_range_finish (ret, r, type, lhs);
+ return float_binary_op_range_finish (ret, r, type, wlhs);
}
virtual bool op2_range (frange &r, tree type,
const frange &lhs,
@@ -2490,13 +2521,14 @@ public:
{
if (lhs.undefined_p ())
return false;
- bool ret = fop_mult.fold_range (r, type, lhs, op2);
+ frange wlhs = float_widen_lhs_range (type, lhs);
+ bool ret = fop_mult.fold_range (r, type, wlhs, op2);
if (!ret)
return ret;
- if (lhs.known_isnan () || op2.known_isnan () || op2.undefined_p ())
- return float_binary_op_range_finish (ret, r, type, lhs);
- const REAL_VALUE_TYPE &lhs_lb = lhs.lower_bound ();
- const REAL_VALUE_TYPE &lhs_ub = lhs.upper_bound ();
+ if (wlhs.known_isnan () || op2.known_isnan () || op2.undefined_p ())
+ return float_binary_op_range_finish (ret, r, type, wlhs);
+ const REAL_VALUE_TYPE &lhs_lb = wlhs.lower_bound ();
+ const REAL_VALUE_TYPE &lhs_ub = wlhs.upper_bound ();
const REAL_VALUE_TYPE &op2_lb = op2.lower_bound ();
const REAL_VALUE_TYPE &op2_ub = op2.upper_bound ();
if ((contains_zero_p (lhs_lb, lhs_ub)
@@ -2512,7 +2544,7 @@ public:
zero_to_inf_range (lb, ub, signbit_known);
r.set (type, lb, ub);
}
- return float_binary_op_range_finish (ret, r, type, lhs);
+ return float_binary_op_range_finish (ret, r, type, wlhs);
}
virtual bool op2_range (frange &r, tree type,
const frange &lhs,
@@ -2521,13 +2553,14 @@ public:
{
if (lhs.undefined_p ())
return false;
- bool ret = fold_range (r, type, op1, lhs);
+ frange wlhs = float_widen_lhs_range (type, lhs);
+ bool ret = fold_range (r, type, op1, wlhs);
if (!ret)
return ret;
- if (lhs.known_isnan () || op1.known_isnan () || op1.undefined_p ())
- return float_binary_op_range_finish (ret, r, type, lhs, true);
- const REAL_VALUE_TYPE &lhs_lb = lhs.lower_bound ();
- const REAL_VALUE_TYPE &lhs_ub = lhs.upper_bound ();
+ if (wlhs.known_isnan () || op1.known_isnan () || op1.undefined_p ())
+ return float_binary_op_range_finish (ret, r, type, wlhs, true);
+ const REAL_VALUE_TYPE &lhs_lb = wlhs.lower_bound ();
+ const REAL_VALUE_TYPE &lhs_ub = wlhs.upper_bound ();
const REAL_VALUE_TYPE &op1_lb = op1.lower_bound ();
const REAL_VALUE_TYPE &op1_ub = op1.upper_bound ();
if ((contains_zero_p (lhs_lb, lhs_ub) && contains_zero_p (op1_lb, op1_ub))
@@ -2542,7 +2575,7 @@ public:
zero_to_inf_range (lb, ub, signbit_known);
r.set (type, lb, ub);
}
- return float_binary_op_range_finish (ret, r, type, lhs, true);
+ return float_binary_op_range_finish (ret, r, type, wlhs, true);
}
private:
void rv_fold (REAL_VALUE_TYPE &lb, REAL_VALUE_TYPE &ub, bool &maybe_nan,
diff --git a/gcc/testsuite/gcc.c-torture/execute/ieee/pr109008.c b/gcc/testsuite/gcc.c-torture/execute/ieee/pr109008.c
new file mode 100644
index 0000000..610aed4
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/ieee/pr109008.c
@@ -0,0 +1,18 @@
+/* PR tree-optimization/109008 */
+
+__attribute__((noipa)) double
+foo (double eps)
+{
+ double d = 1. + eps;
+ if (d == 1.)
+ return eps;
+ return 0.0;
+}
+
+int
+main ()
+{
+ if (foo (__DBL_EPSILON__ / 8.0) == 0.0)
+ __builtin_abort ();
+ return 0;
+}
generated by cgit v1.1 at 2025-08-09 11:35:07 +0000